1)How many Se atoms are there in a 93.2 gram sample of Se ? 2)How many grams of

Question

1)How many Se atoms are there in a 93.2 gram sample of Se ?

2)How many grams of Cr are there in a sample of Cr that contains 3.93×1023atoms?

3)A sample of Na weighs 36.0 grams. Will a sample of Ge that contains the same number of atoms weigh more or less than 36.0 grams? (more, less):

Calculate the mass of a sample of Ge that contains the same number of atoms.
grams of Ge

4)1. How many GRAMS of zinc nitrate are present in 4.29 moles of this compound ?  grams.


2. How many MOLES of zinc nitrate are present in 1.69 grams of this compound ?  moles.
5)1. How many MOLES of carbon tetrafluoride are present in 4.90 grams of this compound ?  moles.



2. How many GRAMS of carbon tetrafluoride are present in 1.36 moles of this compound ?  grams

6)1. How many GRAMS of phosphorus are present in 2.80 moles of phosphorus triiodide ?  grams.


2. How many MOLES of iodine are present in 4.92 grams of phosphorus triiodide ?  moles.

7

Explanation / Answer

1)The no of moles of Se = ( Mass of the Se sample )/Atomic mass of Se= 93.2g/ 79 = 1.179 moles

The no of atoms = NA X No of moles of Se = 6.02X1023 x 1.179 = 7.1 x 1023 atoms

2) The Mass of Cr =   (No of atoms / NA) x atomic mass of Cr = {(3.93×1023)/6.02X1023}x52  

                                                                                            = 33.94 gram

3) Ge has atomic mass much greater than Na so for same mass, the no of atoms will be greater for Na . Because of the smaller atomic mass (Na =23 than 72 =Ge )

                                 No of moles of Na = 36/23 = 1.565 moles

                          For same no of atoms , WE have to take same moles of Ge

                         which is Mass OF Ge =   1,565 x 72.64 =113.69 gram of Ge

How many MOLES of zinc nitrate are present in 1.69 grams of this compound ?  moles.
5)1. How many MOLES of carbon tetrafluoride are present in 4.90 grams of this compound ?  moles. . How many GRAMS of carbon tetrafluoride are present in 1.36 moles of this compound ?  grams

The above questions are incomplete because the compound is not mentioned

6) The Mass of P in 2.8 moles of PI3 = 2.8 moles X 31 = 86.8 gram of P

How many MOLES of iodine are present in 4.92 grams of phosphorus triiodide

   The No of Moles of PI3 are = 4.92 g/412 = .01194 moles of phosphorus triiodide

    The No of Moles of I atoms are   = .01194 x 3 = .03582 moles of atom

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.